﻿using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace ImagesNameConvert
{
    static class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            System.Diagnostics.Process[] processes = System.Diagnostics.Process.GetProcessesByName(Application.CompanyName);
            if (processes.Length > 1)
            {
                Process current = Process.GetCurrentProcess();
                //HandleRunningInstance(current);
                foreach (Process process in Process.GetProcessesByName(current.ProcessName))
                {
                    if (process.Id != current.Id)
                    {
                        int SW_RESTORE = 9;
                        SetForegroundWindow(process.MainWindowHandle);
                        ShowWindowAsync(process.MainWindowHandle, SW_RESTORE);
                        break;
                    }
                }
            }
            else
            {
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.Run(new Form1());
            }

            
        }


        ///<summary>
        /// 该函数设置由不同线程产生的窗口的显示状态
        /// </summary>
        /// <param name="hWnd">窗口句柄</param>
        /// <param name="cmdShow">指定窗口如何显示。查看允许值列表，请查阅ShowWlndow函数的说明部分</param>
        /// <returns>如果函数原来可见，返回值为非零；如果函数原来被隐藏，返回值为零</returns>
        [DllImport("User32.dll")]
        private static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);


        /// <summary>
        ///  该函数将创建指定窗口的线程设置到前台，并且激活该窗口。键盘输入转向该窗口，并为用户改各种可视的记号。
        ///  系统给创建前台窗口的线程分配的权限稍高于其他线程。 
        /// </summary>
        /// <param name="hWnd">将被激活并被调入前台的窗口句柄</param>
        /// <returns>如果窗口设入了前台，返回值为非零；如果窗口未被设入前台，返回值为零</returns>
        [DllImport("User32.dll")]
        private static extern bool SetForegroundWindow(IntPtr hWnd);



        private const int SW_SHOWNOMAL = 1;
        private static void HandleRunningInstance(Process instance)
        {
            ShowWindowAsync(instance.MainWindowHandle, SW_SHOWNOMAL);//显示
        }
    }
}
